The present invention relates generally to bearings for rotary shafts and, more particularly, to bearings for the drive shaft of a wheel-move agricultural irrigation pipe line of the so-called "side-roll" type.
Typically, a wheel-move irrigation apparatus comprises a plurality of sections of pipe which are coupled together into a string which may be as long as a quarter or a half mile. A plurality of wheels are coaxially rigidly fixed at spaced apart points along the string so that when torque is applied to the wheels or pipe the entire string is moved sideways from one area to another in the field to be irrigated. In the end-drive side-roll type of irrigation apparatus, as in my U.S. Pat. Nos. 2,946,515 and 3,147,764, the wheel supported string has a plurality of power transmission units spaced therealong but actuated from a single prime mover at one end of the string through a single drive shaft extending for a major part of the string to the most remote of the power transmission units. The long drive shaft is supported in bearing brackets at intervals to about 6 feet and there may be as many as 200 bearing brackets in a quarter mile line.
As will be apparent from a consideration of my aforementioned patents, there drive shaft bearings are subjected to a rigorous environment in their field of operation. Soils find their way into the ball race and interfere with the free function of the balls in addition to which the abrasive action of the residues entering the bearing eventually bring out permanent damage. Accordingly, it is highly desirable to improve service life by allowing elements trapped within the bearing to be washed out and to bleed out as a result of the sprinkling action and to leave the ball race clear. Additionally, in view of the very great number of bearing brackets which must be employed in a single line, it is highly desirable to devise bearing brackets having a minimum number of parts, minimum material in the parts and a means to assemble the several parts into the completed bearing in an economical fashion. The bearing bracket also should be installable and replaceable with a minimum of tools and skill.